The present invention relates to an exposure apparatus and a method for exposing a pattern formed on a master such as a reticle onto a substrate such as a wafer in a photolithography process for manufacturing a semiconductor element, a liquid crystal display element, or the like, and, more particularly, to a scanning exposure method and an apparatus for a step-and-scan scheme in which the master and substrate are synchronously scanned while part of a pattern on the master is projected onto the wafer, so that the pattern of the master is sequentially transferred to the shot regions on the substrate.
In a conventional photolithography process for manufacturing, e.g., a semiconductor element, liquid crystal display element, image sensing element (e.g., a CCD), or thin-film magnetic head, a cell projection exposure apparatus such as a stepper has been used in which a pattern formed on a master such as a reticle is exposed onto a substrate such as a wafer coated with a photosensitive material.
In recent years, semiconductor device chips have tended to increase in size, and a pattern having a larger area on a reticle must be exposed onto a wafer. A projection exposure apparatus of a step-and-scan scheme is frequently used because it can expose an area larger than the irradiation field (pattern exposure region in a stationary state) of a projection optical system by synchronously scanning the reticle and wafer.
A cell projection exposure apparatus repeats an operation of stepping the shot region of an exposure object to the irradiation field, an operation of aligning the shot region and reticle, and an exposure operation for the shot region.
In a scanning projection (step-and-scan scheme) exposure apparatus, however, a wafer stage is stepped to the scanning start position of the next shot region. The wafer stage and a reticle stage are scanned from the scanning start position to accelerate them so that they reach predetermined scan speeds at the exposure start position. The relative positions of the reticle stage and wafer stage are set with high alignment accuracy. Exposure light irradiation is started to perform scanning exposure by driving the reticle stage and wafer stage at the predetermined scan speed.
Upon completing scanning exposure of one shot, a stepping operation to the next shot in the non-scan direction is started, and at the same time the wafer stage is scanned in the scan direction by a necessary distance in order to set the wafer stage before the start of scanning exposure. The wafer stage is then decelerated. Upon completing scanning in the scan direction, the scan direction is reversed, and then scanning exposure of the next shot is started. The series of operations described above are repeated. The setting distance necessary before the start of scanning exposure is obtained by the product of the scan speed and the time (setting time) required until the vibration generate upon accelerating the wafer stage falls within the allowable range in which the vibration does not interfere with exposure.
At present, the setting time is the sum of a margin and a value obtained by measuring a synchronization error from the end of acceleration and measuring a time until this error falls within the allowable range.
In the conventional scanning projection exposure apparatus, the synchronization setting time of the reticle stage and wafer stage at the time of scanning exposure is determined on the basis of the sum of the margin and the setting time measured beforehand, i.e., on the basis of the worst setting time value. In actual exposure, however, a time within which the synchronization accuracy falls within the allowable range may be shorter than the conventionally used setting time due to factors such as an exposure speed, acceleration, hardware factors, and slight differences in thrust of a linear motor coil serving as a driving source of the wafer stage due to driving coordinate values of the wafer stage. Even in this case, since the setting distance is determined on the basis of the worst setting time value at present, the scan distance is wasted, and an increase in throughput cannot be achieved.
The present invention has been made in consideration of the above situation, and has as its object to shorten the total time required for maintaining synchronization accuracy and improve the throughput by variably setting a setting distance serving as a distance for moving a wafer stage at a uniform velocity in order to guarantee that synchronization error between a master stage and the substrate stage falls within an allowable range.
According the present invention, the foregoing object is attained by providing a scanning exposure apparatus for transferring a pattern of a master onto each shot region while synchronously scanning the master and a substrate on which a plurality of shot regions are arrayed, the apparatus comprising: a master stage for moving the master; a substrate stage for moving the substrate; and a controller for controlling movement of the substrate stage over a plurality of shot regions so as to assure a setting distance serving as a distance for scanning and moving the substrate stage at a uniform velocity in order to guarantee that a synchronization error between the master stage and the substrate stage falls within an allowable range after the substrate stage is accelerated up to a scan speed for scanning exposure, wherein the controller controls the movement of the substrate stage such that a setting distance for a first shot region to be scanned and exposed upon a change in row to which a shot region of an exposure object belongs is set to be longer than a setting distance for other shot regions.
In a preferred embodiment, the controller controls the continuous movement of the substrate stage in accordance with a common setting distance for shot regions other than the first shot region to be scanned and exposed among a plurality of shot regions belonging to one row.
In a preferred embodiment, the controller controls the continuous movement of the substrate stage in accordance with a setting distance determined for each row to which a plurality of shot regions belong.
In a preferred embodiment, the setting distance is determined on the basis of a setting time until a synchronization error between the master stage and the substrate stage falls within an allowable range after the substrate stage is accelerated up to a scan speed for scanning exposure.
According to another aspect of the present invention, the foregoing object is attained by providing a scanning exposure apparatus for transferring a pattern of a master onto each shot region while synchronously scanning the master and a substrate on which a plurality of shot regions are arrayed, the apparatus comprising: a master stage for moving the master; a substrate stage for moving the substrate; and a controller for controlling movement of the substrate stage for a plurality of shot regions so as to assure a setting distance serving as a distance for scanning and moving the substrate stage at a uniform velocity in order to guarantee that a synchronization error between the master stage and the substrate stage falls within an allowable range after the substrate stage is accelerated up to a scan speed for scanning exposure, wherein the controller controls movement of the substrate stage in accordance with a setting distance determined for each row to which a plurality of shot regions belongs.
In a preferred embodiment, the setting distance is determined on the basis of a setting time until a synchronization error between the master stage and the substrate stage falls within an allowable range after the substrate stage is accelerated up to a scan speed for scanning exposure.
According to another aspect of the present invention, the foregoing object is attained by providing a scanning exposure method of transferring a pattern of a master onto each shot region while synchronously scanning the master and a substrate on which a plurality of shot regions are arrayed, the method comprising: the control step of controlling movement of a substrate stage for a plurality of shot regions so as to assure a setting distance serving as a distance for scanning and moving the substrate stage at a uniform velocity in order to guarantee that a synchronization error between a master stage and the substrate stage falls within an allowable range after the substrate stage is accelerated up to a scan speed for scanning exposure, wherein in the control step, the movement of the substrate stage is controlled such that a setting distance for a first shot region to be scanned and exposed upon a change in row to which a shot region of an exposure object belongs is set to be longer than a setting distance for other shot regions.
In a preferred embodiment, in the control step, the continuous movement of the substrate stage is controlled in accordance with a common setting distance for shot regions other than the first shot region to be scanned and exposed among a plurality of shot regions belonging to one row.
In a preferred embodiment, in the control step, the continuous movement of the substrate stage is controlled in accordance with a setting distance determined for each row to which a plurality of shot regions belongs.
In a preferred embodiment, the setting distance is determined on the basis of a setting time until a synchronization error between the master stage and the substrate stage falls within an allowable range after the substrate stage is accelerated up to a scan speed for scanning exposure.
According to another aspect of the present invention, the foregoing object is attained by providing a scanning exposure method of transferring a pattern of a master onto each shot region while synchronously scanning the master and a substrate on which a plurality of shot regions are arrayed, the method comprising: the control step of controlling movement of a substrate stage for a plurality of shot regions so as to assure a setting distance serving as a distance for scanning and moving the substrate stage at a uniform velocity in order to guarantee that a synchronization error between a master stage and the substrate stage falls within an allowable range after the substrate stage is accelerated up to a scan speed for scanning exposure, wherein in the control step, movement of the substrate stage is controlled in accordance with a setting distance determined for each row to which a plurality of shot regions belongs.
In a preferred embodiment, the setting distance is determined on the basis of a setting time until a synchronization error between the master stage and the substrate stage falls within an allowable range after the substrate stage is accelerated up to a scan speed for scanning exposure.
According to another aspect of the present invention, the foregoing object is attained by providing a semiconductor device manufacturing method comprising the steps of: installing manufacturing apparatuses, for performing various processes, including the above scanning exposure apparatus in a semiconductor manufacturing factory, and manufacturing a semiconductor device in a plurality of processes by using the manufacturing apparatuses.
According the preferred embodiment of the present invention, the method may comprise the steps of: connecting the manufacturing apparatuses by a local area network; and communicating information about at least one of the manufacturing apparatuses between the local area network and an external network of the semiconductor manufacturing factory.
According to the preferred embodiment of the present invention, the method may comprise the step of acquiring maintenance information of the scanning exposure apparatus by accessing a database provided by a vendor or user of the scanning exposure apparatus via the external network.
According to another aspect of the present invention, the foregoing object is attained by providing a semiconductor manufacturing factory comprising: manufacturing apparatuses for performing various processes including the above scanning exposure apparatus; a local area network for connecting the manufacturing apparatuses; and a gateway for allowing the local area network to access an external network of the factory, wherein information about at least one of the manufacturing apparatuses is communicated.
According to another aspect of the present invention, the foregoing object is attained by providing a maintenance method for the above scanning exposure apparatus that is installed in a semiconductor manufacturing factory, the method comprising the steps of: causing a vendor or user of the scanning exposure apparatus to provide a maintenance database connected to an external network of the semiconductor manufacturing factory; authenticating access from the semiconductor manufacturing factory to the maintenance database via the external network; and transmitting maintenance information accumulated in the maintenance database to the semiconductor manufacturing factory via the external network.
According to the preferred embodiment of the present invention, the apparatus may comprise: a display, a network interface and a computer for executing network software, wherein maintenance information of the scanning exposure apparatus can be communicated via a computer network.
In a preferred embodiment, the network software is connected to an external network of a factory where the scanning exposure apparatus is installed, provides on the display a user interface for accessing a maintenance database provided by a vendor or user of the scanning exposure apparatus, and enables obtaining information from the database via the external network.
According to the present invention, the foregoing object is attained by providing a semiconductor device manufacturing method comprising the steps of: installing manufacturing apparatuses, for performing various processes, including the above scanning exposure apparatus, in a semiconductor manufacturing factory; and manufacturing a semiconductor device in a plurality of processes by using the manufacturing apparatuses.
According to the preferred embodiment of the present invention, the method may comprise the steps of: connecting the manufacturing apparatuses by a local area network; and communicating information about at least one of the manufacturing apparatuses between the local area network and an external network of the semiconductor manufacturing factory.
According to the preferred embodiment of the present invention, the method may comprise the step of acquiring maintenance information of the scanning exposure apparatus by accessing a database provided by a vendor or user of the scanning exposure apparatus via the external network.
According to another aspect of the present invention, the foregoing object is attained by providing a semiconductor manufacturing factory comprising: manufacturing apparatuses, for performing various processes, including the above scanning exposure apparatus; a local area network for connecting the manufacturing apparatuses; and a gateway for allowing the local area network to access an external network of the factory, wherein information about at least one of the manufacturing apparatuses is communicated.
According to another aspect of the present invention, the foregoing object is attained by providing a maintenance method for the above scanning exposure apparatus that is installed in a semiconductor manufacturing factory, the method comprising the steps of: causing a vendor or user of the scanning exposure apparatus to provide a maintenance database connected to an external network of the semiconductor manufacturing factory; authenticating access from the semiconductor manufacturing factory to the maintenance database via the external network; and transmitting maintenance information accumulated in the maintenance database to the semiconductor manufacturing factory via the external network.
According to the preferred embodiment of the present invention, the apparatus may comprise: a display; a network interface; and a computer for executing network software, wherein maintenance information of the scanning exposure apparatus can be communicated via a computer network.
In a preferred embodiment, the network software is connected to an external network of a factory where the scanning exposure apparatus is installed, provides on the display a user interface for accessing a maintenance database provided by a vendor or user of the scanning exposure apparatus, and enables obtaining information from the database via the external network.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.